66684067789 has 2 divisors, whose sum is σ = 66684067790. Its totient is φ = 66684067788.

The previous prime is 66684067759. The next prime is 66684067799. The reversal of 66684067789 is 98776048666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44922802500 + 21761265289 = 211950^2 + 147517^2 .

It is a cyclic number.

It is not a de Polignac number, because 66684067789 - 2⁹ = 66684067277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66684067759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33342033894 + 33342033895.

It is an arithmetic number, because the mean of its divisors is an integer number (33342033895).

Almost surely, 2^66684067789 is an apocalyptic number.

It is an amenable number.

66684067789 is a deficient number, since it is larger than the sum of its proper divisors (1).

66684067789 is an equidigital number, since it uses as much as digits as its factorization.

66684067789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 146313216, while the sum is 67.

The spelling of 66684067789 in words is "sixty-six billion, six hundred eighty-four million, sixty-seven thousand, seven hundred eighty-nine".